Method for incorporating alkyl ester endgroups to improve the release properties of melt polycarbonate

a technology of alkyl ester and endgroup, which is applied in the field of endcapping polycarbonate resins and to endcapping compositions, can solve the problems of two step process, significant cost increase of end-capping reagent, and not without drawbacks, and achieve high level of end-capping of chains, high stability of resulting polycarbonate, and high degree of completion

Active Publication Date: 2006-09-12
SHPP GLOBAL TECH BV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This approach results in a high level of end-capping efficiency, reducing production costs and impurities, and improving the stability and mold release properties of polycarbonates, while minimizing 'plate-out' issues during molding, thus streamlining the production process.

Problems solved by technology

While such end-capping reagents may be effective, they are not without their drawbacks.
This two step process adds significantly to the cost of the end-capping reagent.
An additional deficiency of this method is that the asymmetric mixed carbonates prepared in this way are often contaminated with traces of nitrogen- and halogen-containing impurities and with symmetrical carbonates derived from one or both of the phenols used in the reaction.
As a consequence, in order to obtain materials of suitable quality for polymerization, purification is often both essential and difficult.

Method used

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  • Method for incorporating alkyl ester endgroups to improve the release properties of melt polycarbonate
  • Method for incorporating alkyl ester endgroups to improve the release properties of melt polycarbonate
  • Method for incorporating alkyl ester endgroups to improve the release properties of melt polycarbonate

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0071]A batch reactor tube was charged under nitrogen with 25 g of polycarbonate A and 0.9241 g (3.25×10−3 mole) of stearic acid and 0.5364 g of bis(methyl salicyl) carbonate or bMSC (1.62×10−3 mole). Thus the stearic acid was added in a molar ratio of 1.0 relative to the free OH content of the polycarbonate A, and the bMSC in a molar ratio of 0.5 relative to the free OH content of the polycarbonate A. The mixture was heated to a temperature of 270° C. and stirred for 10 minutes. After the melt mixing stage a vacuum was applied to the system at a pressure of 0.5 mbar and the reaction continued for 40 minutes. After the reaction stage, a colorless polymer was recovered from the reaction tube. The results are shown in Table 2.

example 2

[0072]Example 1 was repeated but instead of adding 1.0728 g (3.25×10−3 mole) of bis(methyl salicyl) carbonate or bMSC, 0.9656 g (2.92×10−3 mole) of bMSC was charged to the reactor tube. After the reaction stage, a colorless polymer was sampled from the reaction tube. The results are shown in Table 2.

example 3

[0073]Example 1 was repeated but instead of adding 1.0728 g (3.25×10−3 mole) of bis(methyl salicyl) carbonate or bMSC, 1.0728 g (3.25×10−3 mole) of bMSC was charged to the reactor tube. After the reaction stage, a colorless polymer was sampled from the reaction tube. The results are shown in Table 2.

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Abstract

Alkyl ester end-capped polycarbonates have improved release properties and may be produced by a method comprising the step of combining a polycarbonate having free terminal OH groups with an end-capping reagent comprising a symmetrical activated carbonate and an alkyl ester, whereby the end-capping reagent reacts with at least some of the free hydroxyl end groups of the polycarbonate to produce an end-capped polycarbonate comprising optionally substituted aliphatic ester end groups.

Description

BACKGROUND OF THE INVENTION[0001]This application relates to a method for end-capping polycarbonate resins and to end-capping compositions useful in such a method.[0002]Polycarbonate is excellent in mechanical properties such as impact resistance and is also excellent in heat resistance and transparency, and it is widely used in industrial application. As a method of producing a polycarbonate, there is known a method in which phosgene is directly reacted with an aromatic diol such as bisphenol A (a.k.a. the interfacial polymerization method) or in which an aromatic dihydroxy compound such as bisphenol and a diaryl carbonate such as diphenyl carbonate are reacted in ester exchange in a molten state (a.k.a. melt-polycondensation method).[0003]Polycarbonates prepared by a melt transesterification process generally contain significant levels of uncapped chains (7–50%) as compared to interfacially prepared polycarbonates. These uncapped chains can have a significant impact on the resulti...

Claims

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Application Information

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Patent Type & AuthorityPatents(United States)
IPC IPC(8): C08G64/00
CPCC08G64/42C08G2650/04
InventorBRACK, HANS-PETERKARLIK, DENNISLENS, JAN PLEUN
OwnerSHPP GLOBAL TECH BV